Blank for forming a cover plate



R. L. SMIRL April 16, 1968 BLANK FOR FORMING A COVER PLATE I5 Sheets-Sheet L Original Filed Dec. 30, 1964 RICHARD L. SM/RL.

ATTY

April 16, 1968 R. SMIRL BLANK FOR FORMING A COVER PLATE 5 Sheets-Sheet.

Original Filed Dec. 30, 1964 ATTY.

R. L. SMIRL BLANK FOR FORMING A COVER PLATE April 16, 1968 Original Filed Dec. 50, 1964' 5 Sheets-Sheet (5 FIG.9

FIG. I

FIGJO INVENTOR RICHA RD L. SM/RL United States Patent ABSTRACT OF THE DISCLOSURE A blank for forming a sheet metal cover plate, comprising: a fiat sheet metal body provided with equi-spaced trapezoidal areas arranged about a geometrical center of said blank, elongated Webs interconnecting the innermost adjacent corners of said areas, each said areas having a pear-shaped opening provided therein.

The present invention is a divisional application of Ser. No. 422,107, filed Dec. 30, 1964, entitled, Cover Plate for Friction Device, now Patent No. 3,335,595.

This invention relates to an automotive type friction clutch and more particularly to the product and process of manufacturing a stamped sheet metal cover plate for clutches of the disc type.

A primary object of this invention is to provide a process for manufacturing a sheet metal cover plate for a disc type automotive clutch which substantially eliminates the number of manufacturing steps required to provide a finished cover plate with the necessary configuration and appropriate surfaces; the manufacturing method envisioned by this invention comprises a maximum of two steps wherein a fiat sheet metal piece is blanked and then subsequently shaped into a three-dimensional cover plate by a single stamping operation resulting in the completed product.

Another object of this invention is to provide a novel method and product for a clutch cover plate which enables the resulting cover plate to have mounting stations closely positioned to the outer periphery of the friction elements enclosed therein without sacrificing strength for withstanding reaction loads.

Yet another object of this invention is to provide a unique cover plate and method of manufacturing which results in a product having mounting stations equally circumferentially spaced and interconnected by chordally disposed webs, the mounting stations being substantially comprised of conical sections integrated with each other by sharp radii, the cover plate being of a type to accommodate a rockable strut connection with a clutch actuating assembly (there being no positive connection between the cover plate and the lever actuating system).

Other objects and advantages of this invention will become more apparent from the following detailed description taken in connection with the accompanying drawings in which:

FIGURE 1, is a plan view, partially broken away, of a cover plate representing the product and manufactured by the process embodying the principles of this invention; other elements with which the cover plate cooperates are shown in phantom outline;

FIGURE 2, is a fragmentary sectional view taken substantially along line 2-2. of FIGURE 1;

FIGURE 3, is a sectional view taken substantially along line 3-3 of FIGURE 1;

FIGURE 4, is an enlarged fragmentary sectional view of a mounting portion of the cover plate shown in FIG- URE 1 (taken substantially along line 4-4);

3,378,358 Patented Apr. 16, 1968 ice FIGURE 5 is a fragmentary view taken substantially along line 5-5 of FIGURE 4;

FIGURE 6, is a reduced illustration of the blank from which the cover plate is stamped in a single operation;

FIGURE 7, is a fragmentary elevational view of FIG- URE 6;

FIGURE 8 is a sectional view taken substantially along line 8-8 of FIGURE 1;

FIGURE 9, is a section view taken substantially along line 9-9 of FIGURE 8;

FIGURE 10, is a section view taken substantially along line 10-10 of FIGURE 8; and

FIGURE 11, is a view taken along line 11-11 of FIGURE 9.

Turning now to the drawings and more particularly to FIGURES 1-5, a sheet metal cover plate A is illustrated as drivingly coupled with an annular flywheel B, the flywheel and cover plate constituting rotative input means for the clutch device, the latter assembly broadly designated 10. Rotative driven means C comprises a frictional disc C1 drivingly splined to an output shaft C-2. An actuating assembly D comprises a plurality of radially disposed levers D-l fulcrumed on the annular pressure plate E, the levers applying a working force to the pressure plate as received from a thrust bearing D-4 and reacting against the cover plate by way of a plurality of struts D-2. The actuating assembly is eflective to urge the pressure plate (strapped to the cover plate by means 9) toward the flywheel and thereby clamp the. rotative driven means C therebetween and provide for conjoint rotation.

Apart from the cover plate A, the above elements are considered typical in the art and will not be further described.

Turning now to the cover plate A, the resulting prod- 'uct configuration will be described, followed by descrip tion of the process of manufacturing. The cover plate comprises a plurality of equi-spaced mounting portions or stations 11 having a stepped side wall 12, the stepped side wall having a radially outwardly extending lip 13 provided with pads 14 (segments of a circle) effective to receive the fasteners (such as cap screws 15) extending through openings 16 generally centered in the pads. The mounting stations 11, are interconnected by chordally disposed webs 17, each of the webs and the upper portion 18 of the mounting stations being integrated together to form a rear wall 19 of the cover plate which is spaced from the common plane within which said lips 13 are disposed. The side edges 13:: of the lips are aligned with the outer contour 17a of webs 17, as illustrated in FIGURE 1.

The rear wall 19 comprised of the chordal webs and upper portions 18 of each step 12, is provided with an inner peripheral flange 21 extending rearwardly of the device as illustrated in FIGURES 3 and 5.

The mounting stations are provided with several specific contours each of which are important to the effective functioning of the cover plate in the clutch device. The upper portions 1'8 of the steps 12 have a chordal pocket 22 with an inwardly facing semi-cylindrical surface 22a. The surface 22a is efiective to rockably receive one of edges of the struts D-2. The outer periphery of the webs 17 is provided with an inwardly facing flange 23 which integrates into the side wall 24 of the steps 12.

Both the upper portion 18 and the side wall 24 of the steps 12 are formed of conically shaped sections interconnected by sharp bends or radii 2.5, augmented by the indented pockets 22 and the inner peripheral flange 21 to add axial rigidity to the sheet metal mounting stations at those locations; this provides a more stabilized cover plate while at the same time maintaining the economy of sheet metal construction. Flat sections at the back wall and mounting stations is to be avoided since flexure is more likely under reaction loads applied against them.

In the side wall 24 of each step 12, an access opening 26 is provided with generally inwardly curved edge contours 26a and 2612 so as to maintain the center 27 of the bolt openings 16 in each pad as close as possible to the outer periphery of the enclosed elements of the clutch device. The geometry of such positioning enables the reaction loads applied to the cover plate to be as close as possible to the points at which the plate is mounted to the flywheel while at the same time providing a rear wall positioned to receive reaction forces to move the pressure plate.

The process of forming the resulting cover plate above described, in a simplified two step sequence, requires particular definition of a flat blank from which the cover plate may be stamped into three-dimensional contour by a single stroke. As shown in FIGURE 6, the first step of the process comprises blanking of a flat piece 30 having a plurality of generally trapezoidal areas 31, opposite sides 32 and 33 of the areas 31 slightly converging as they approach the end 44 thereof. Webs 34 extend on a bias between the areas 31 and interconnect the inner adjacent corners 31a of said trapezoidal areas. Each area 31 has a pear shaped opening 35 with a greater axis 36 transverse to a radius from center 38; the axis 37 of the opening bisects the area 31 and has an edge 35a positioned outwardly from the center 38 of the blank a distance 39 sufficient so that on three-dimensional forming of the blank, the inner edge 26a of the pads 14 will be at a predetermined distance from the center of the device Positioning of edge 35a from the inner periphery 40 of the blank is generally equal to the composite dimension, taken on the resulting product, comprised of the width of the upper portion 18 of steps 12 and the extent of side wall 24.

Each of the webs 34 are provided with a generally straight inner edge 40a and a slightly bowed outer edge 44a which tends to narrow at the intersection of the webs with the trapezoidal areas 31. This is elfective to accommodate folding of the areas 31 into the stepped mounting stations 12 whereby some of the metal material will be forced toward the web and thereby provide the resulting alignment of the resulting edge 1311 with flange 23 in the three-dimensional cover plate.

During the stamping operation, circular openings 16 are simultaneously provided with centers 27 thereof aligned with the axis 37 of openings 35; the openings 16 are spaced outwardly of edge 26a a distance less than the distance the opening 16 is spaced from the outer edge 44 of the lips 13.

From the above characterized blank, the three-dimensional cover plate may be obtained by a single stamping stroke. During such steps, the outer portions of sides 32 and 33 of the blank will become edges 13a which are in alignment with the inwardly directed chordal flanges 23 and the webs will have a resulting straight periphery 17a. The openings 35 will be stretched into a different plane and configuration so that edge 35a and edge 35b will be generally lapped one above each other to provide an access for the more closely positioned cap screws 15 extending through openings 16. The pockets 22 and conical sections 18 and 24 will be formed adding inherent axial rigidity.

While I have described my invention in connection with one specific embodiment and other alternative suggestions thereof, it is understood that this is by way of illustration and not by way of limitation and the scope of my invention is defined solely by the appended claims which should be construed as broadly as the prior art will permit.

I claim:

1. A blank for forming a sheet metal cover plate, comprising: a fiat sheet metal body provided with equi-spaced trapezoidal areas arranged about a geometrical center of said blank, each of said areas having side edges generally converging outwardly, elongated webs interconnecting the innermost adjacent corners of said areas and having a web outer edge slightly bowed outwardly, each said areas having a pear-shaped opening provided therein with a minor axis generally bisecting the sides of said areas and a nose directed radially inwardly.

2. A blank as in claim 1, in which the outer edge of each of said openings is spaced from the outer edge of said areas a distance slightly greater than the dimension of said opening along the minor axis.

3. A blank as in claim 1, in which the minor axis of each of said openings passes through the geometrical center of said blank.

References Cited UNITED STATES PATENTS 1,709,110 4/1929 Bessonett 29190 2,053,490 9/1936 Novick 29-190 2,602,988 7/1952 Klym 29-190 3,248,184 4/1966 Osborn, et al. 29190 DAVID L. RECK, Primary Examiner.

RICHARD O. DEAN, Examiner. 

